Wow... lots of different stuff there
The Stoker, PartyQ and others are fan control devices to control smoker temp. I've never found the need for one on a WSM since they run very well as designed, but having one will give you better efficiency and allow you to monitor the WSM temp and possible meat temp (depending on the controller) from outside the WSM.
The Maverick is a remote thermometer. It will allow you to monitor smoker temp and meat temp at a distance. It is not a temperature controller.
The Thermapen is an instant reading thermometer. It will allow you to read the internal temp of the meat quickly.
They all have their place, but none are absolutely necessary. They can be helpful, however, and lots of the gang have one, two or all three
As far as this statement...
It looks basically like i can just get the internal temps an then know when to take the meat off the grill or smoker right?
That's one danger of using the Stoker/PartyQ or Maverick. With meats like brisket, pork butt, chuck roast, ribs and some others you really can't go by internal temperature. Each piece of meat is different and some will be done at 190 internal but some may not be done until 205 internal (or even higher for a chuck roast). Your best bet is to use the controller or remote thermometer to monitor temps and then use a slim probe like a skewer or a thermometer probe to test for done by feel. For ribs you can use the bend test or a toothpick to test for done.
I hope this all helps and that I didn't confuse thing more